Conventionally, imaging devices of a complementary metal oxide semiconductor (CMOS) type are used as imaging devices used for cameras and the like. This imaging device has a pixel array unit in which pixels including a photoelectric conversion unit are arranged in a two-dimensional shape. Here, the photoelectric conversion unit is a semiconductor element which performs photoelectric conversion for generating charge corresponding to the amount of incident light. A period during which this photoelectric conversion is performed corresponds to an exposure period in the imaging device. The exposure period and a signal reading period for reading charge generated in the exposure period as a signal are alternately performed and image signals of consecutive frames can be thereby obtained. In this imaging device, in order to generate an image signal of one frame, it is necessary to read image signals of all the rows. Reading of these signals is performed sequentially row by row. In a conventional CMOS type imaging device, exposure is started immediately after signal reading. Therefore, timings of start and end of exposure are shifted by every row and thus there is a problem that distortion occurs in an output image.
Therefore, there has been proposed an imaging device having a global shutter function for starting and ending exposure simultaneously for all lines (see, for example, Patent Document 1).